Update the README

Author: SimonSapin

README.md

@@ -1,16 +1,14 @@
 rust-cssparser
 ==============
 
-WIP rust implementation of the 2013 version of
+Rust implementation of the 2013 version of
 [css3-syntax](http://dev.w3.org/csswg/css3-syntax/)
 
 
 TODO
 ----
 
-* [x] Tokenization
-* [x] Declaration and rule parsing
-* [ ] Detect character encoding & decode from bytes
-* [ ] Track line/column number for tokens.
-* [ ] Figure out float and integer overflow
-* [ ] Make it fast!
+* Detect character encoding & decode from bytes
+* Figure out float and integer overflow
+* Serialize tokens back to CSS
+* Make it fast!